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I just purchased an 05 645ci convertible. When I let the top down, there is a whitish/bluish stain on the cover. I suppose it is oxidation. Does this have to be painted over or is there some sort of chemical based solution that would remove it? I've tried general household cleaners diluted with parts water, but no success. Its on both the driver and passenger side of the covering.

I may have not been descript enough about my issue. It's not the ragtop at all, but rather the plastic cover that hides the top after it has been dropped. It appears to be rings left by the seal or something. I will post pics of it shortly....

Ahhh - you mean discoloration on the boot. Yes - I had that in my last 6er convertible. I couldn't get rid of it. Does it only show after it's been wet (like after a wash or rain)? That's what mine did.

Thanks for the quick replies. I haven't been on here in a while b/c advanced statistics is doing the kung fu in my you know what (doctoral student)....i will definitely try the black shoe polish...should i use gloss or flat? I suppose flat would be the safe route in terms of ensuring the color blends well. Sounds like the excellent low cost remedy.

I got rid of the oxidation I had (see the first pic below) by using Forever Black Bumper Trim. I taped up the edges of the Convertible Boot with Scotch Blue Painters Tape for Delicate Surfaces and applied two coats of Forever Black, allowing drying in between coats. While you can still see the runner seal placement lines on the boot (as I could before - the green only showed up when the boot was wet and/or cold and would take awhile to return to black), you can see that the boot at very least looks just black (second pic).

I'm much happier. I should've done this on my 645 - she had it worse and it always bothered me. BTW, it also looks a good number of shades darker, which I like.

I tip my hat to you for a very good follow-up to a question I asked months ago. Thank you for being diligent about finding a solution. I'm headed to a Forever Black dealer to purchase some now.

Thanks Top Down.

Quite welcome! I've also redone my wife's Expedition. It came out looking new! Take lots of time taping up the edges - this stuff will stain! As long as you're careful and detailed in your taping, all will be well. Keep the spread even (it bubbles up here and there) to avoid streaks.

Zaino Z-16 Perfect Tire Gloss.
I discovered this stuff when trying to keep the wife's Volvo XC70 vinyl cladding looking good - after tryng literally every solution suggested by previous posters. I'm not sure why Sal calls it a Tire Gloss - he markets it as a "rubber and exterior vinyl finishing treatment" and it is absolutely the best product I've found for exterior vinyl (but I don't use it on my tires). I don't like silicone-based dressings of any kind for any purpose and this stuff contains absolutely no silicone. And it works!

I will admit that I'm an unabashed Zaino fan and that my top spends very little time in the closed position.

I got rid of the oxidation I had (see the first pic below) by using Forever Black Bumper Trim. I taped up the edges of the Convertible Boot with Scotch Blue Painters Tape for Delicate Surfaces and applied two coats of Forever Black, allowing drying in between coats. While you can still see the runner seal placement lines on the boot (as I could before - the green only showed up when the boot was wet and/or cold and would take awhile to return to black), you can see that the boot at very least looks just black (second pic).

I'm much happier. I should've done this on my 645 - she had it worse and it always bothered me. BTW, it also looks a good number of shades darker, which I like.

Quite welcome and you won't be disappointed. It's not a completely perfect solution, but your boot will certainly look black. I would suggest some bi-weekly touch up using something like 303 Aerospace Protectant - this will protect the boot and keep it looking new.